Ivacaftor which is chemically known as N-(2,4-di-tert-butyl-5-hydroxyphenyl)-1,4-dihydro-4-oxoquiniline-3-carboxamide is represented structurally by a compound of formula I.

Ivacaftor is classified as a cystic fibrosis transmembrane conductance regulator potentiator. Ivacaftor is commercially available as Kalydeco® in the form of pharmaceutical preparations. Kalydeco® is indicated for the treatment of cystic fibrosis in patients age 6 years and older who have a G55ID mutation in the CFTR gene.
U.S. Pat. No. 7,495,103 discloses ivacaftor, a process for its preparation and its intermediates, wherein the process utilizes column chromatography and high performance liquid chromatography (HPLC) purification processes.
Polymorphism is the occurrence of different crystalline forms of a single compound and it is a property of some compounds and complexes. Thus, polymorphs are distinct solids sharing the same molecular formula, yet each polymorph may have distinct physical properties. Therefore, a single compound may give rise to a variety of polymorphic forms where each form has different and distinct physical properties, such as different solubility profiles, different melting point temperatures and/or different x-ray diffraction peaks. Since the solubility of each polymorph may vary, identifying the existence of pharmaceutical polymorphs is essential for providing pharmaceuticals with predicable solubility profiles. It is desirable to investigate all solid state forms of a drug, including all polymorphic forms, and to determine the stability, dissolution and flow properties of each polymorphic form. Polymorphic forms of a compound can be distinguished in a laboratory by X-ray diffraction spectroscopy and by other methods such as, infrared spectrometry. Additionally, polymorphic forms of the same drug substance or active pharmaceutical ingredient, can be administered by itself or formulated as a drug product (also known as the final or finished dosage form), and are well known in the pharmaceutical art to affect, for example, the solubility, stability, flowability, tractability and compressibility of drug substances and the safety and efficacy of drug products. Therefore, there is a continuing need for new crystalline forms and new processes of preparing crystalline forms.
The present invention relates to various forms of ivacaftor.